Greenland is calling on Denmark to clean up an abandoned under-ice missile project and other US military installations left to rust in the pristine landscape after the Cold War.

The 1951 deal under which Nato member Denmark allowed the US to build 33 bases and radar stations in the former Danish province does not specify who is responsible for any cleanup.

Tired of waiting, Greenland's leaders are now urging Denmark to remove the junk that the Americans left behind, including Camp Century, a never-completed launch site for nuclear missiles under the surface of the massive ice cap.

"Unless Denmark has entered other agreements with the United States about Camp Century, the responsibility for investigation and cleanup lies with Denmark alone," said Vittus Qujaukitsoq, Greenland's minister in charge of foreign affairs.

Camp Century was built in 1959-60 in north-western Greenland, officially to test sub-ice construction techniques. The real plan was top secret: creating a hidden launch site for ballistic missiles that could reach the Soviet Union.

The project was abandoned in 1966 because the ice cap began to crush the camp. The US removed a portable nuclear reactor that had supplied heat and electricity, but left an estimated 200,000 litres of diesel oil and sewage, according to an international study published in August.

Scientists are warning that as global warming melts the ice cap, the waste could surface and pollute the environment.

In an October 24 letter to Danish Foreign Minister Kristian Jensen, obtained by The Associated Press, Qujaukitsoq asked about Denmark's plans for Camp Century, adding that an international study said the waste includes "radioactivity, oil and PCB pollution".

PCB stands for polychlorinated biphenyl, a man-made chemical once widely used in paints, plastics and other products, banned after it was demonstrated to cause cancer and other ailments.

At a meeting on November 17 in Nuuk, the Greenland capital, to discuss the issue, Mr Jensen said Denmark's Environment Ministry was investigating the environmental risks.

"I hope it can be done as quickly as possible," he told a news conference, declining to give any specifics.

He later told The Associated Press in an email that "it is still too early to say who will be involved in a possible cleanup".

The US military was interested in Greenland during the Cold War due to its strategic location in the Arctic. Under the 1951 agreement, the US also built four radar stations as part of an early warning system to detect incoming Soviet bombers.

The US Air Force still uses the Thule Air Base, about 745 miles below the North Pole. Military airfields in Narsarsuaq, Kulusuk and Kangerlussuaq have become civilian airports.

Several other military installations have been abandoned, some in remote areas, in the hope they would be entombed forever in the thick ice cap that covers most of the vast island.